<template>
  <view
    class="tui-circular-container"
    :style="{ width: diam + 'px', height: (height || diam) + 'px' }"
  >
    <canvas
      class="tui-circular-default"
      :canvas-id="defaultCanvasId"
      :id="defaultCanvasId"
      :style="{ width: diam + 'px', height: (height || diam) + 'px' }"
      v-if="defaultShow"
    ></canvas>
    <canvas
      class="tui-circular-progress"
      :canvas-id="progressCanvasId"
      :id="progressCanvasId"
      :style="{ width: diam + 'px', height: (height || diam) + 'px' }"
    ></canvas>
    <slot />
  </view>
</template>

<script>
export default {
  name: 'tuiCircularProgress',
  emits: ['change', 'end'],
  props: {
    /*
			  传值需使用rpx进行转换保证各终端兼容
			  px = rpx / 750 * wx.getSystemInfoSync().windowWidth
			  圆形进度条(画布)宽度，直径 [px]
			*/
    diam: {
      type: Number,
      default: 60,
    },
    //圆形进度条(画布)高度，默认取diam值[当画半弧时传值，height有值时则取height]
    height: {
      type: Number,
      default: 0,
    },
    //进度条线条宽度[px]
    lineWidth: {
      type: Number,
      default: 4,
    },
    /*
			 线条的端点样式
			 butt：向线条的每个末端添加平直的边缘
			 round	向线条的每个末端添加圆形线帽
			 square	向线条的每个末端添加正方形线帽
			*/
    lineCap: {
      type: String,
      default: 'round',
    },
    //圆环进度字体大小 [px]
    fontSize: {
      type: Number,
      default: 12,
    },
    //圆环进度字体颜色
    fontColor: {
      type: String,
      default: '#5677fc',
    },
    //是否显示进度文字
    fontShow: {
      type: Boolean,
      default: true,
    },
    /*
			 自定义显示文字[默认为空，显示百分比，fontShow=true时生效]
			 可以使用 slot自定义显示内容
			*/
    percentText: {
      type: String,
      default: '',
    },
    //是否显示默认(背景)进度条
    defaultShow: {
      type: Boolean,
      default: true,
    },
    //默认进度条颜色
    defaultColor: {
      type: String,
      default: '#CCC',
    },
    //进度条颜色
    progressColor: {
      type: String,
      default: '#5677fc',
    },
    //进度条渐变颜色[结合progressColor使用，默认为空]
    gradualColor: {
      type: String,
      default: '',
    },
    //起始弧度，单位弧度
    sAngle: {
      type: Number,
      default: -Math.PI / 2,
    },
    //指定弧度的方向是逆时针还是顺时针。默认是false，即顺时针
    counterclockwise: {
      type: Boolean,
      default: false,
    },
    //进度百分比 [10% 传值 10]
    percentage: {
      type: Number,
      default: 0,
    },
    //进度百分比缩放倍数[使用半弧为100%时，则可传2]
    multiple: {
      type: Number,
      default: 1,
    },
    //动画执行时间[单位毫秒，低于50无动画]
    duration: {
      type: Number,
      default: 800,
    },
    //backwards: 动画从头播；forwards：动画从上次结束点接着播
    activeMode: {
      type: String,
      default: 'backwards',
    },
  },
  watch: {
    percentage(val) {
      this.initDraw();
    },
  },
  data() {
    return {
      // #ifdef MP-WEIXIN
      progressCanvasId: 'progressCanvasId',
      defaultCanvasId: 'defaultCanvasId',
      // #endif
      // #ifndef MP-WEIXIN
      progressCanvasId: this.getCanvasId(),
      defaultCanvasId: this.getCanvasId(),
      // #endif
      progressContext: null,
      linearGradient: null,
      //起始百分比
      startPercentage: 0,
      // dpi
      //pixelRatio: uni.getSystemInfoSync().pixelRatio
    };
  },
  mounted() {
    this.initDraw(true);
  },
  methods: {
    //初始化绘制
    initDraw(init) {
      let start = this.activeMode === 'backwards' ? 0 : this.startPercentage;
      start = start > this.percentage ? 0 : start;
      if (this.defaultShow && init) {
        this.drawDefaultCircular();
      }
      this.drawProgressCircular(start);
    },
    //默认(背景)圆环
    drawDefaultCircular() {
      let ctx = uni.createCanvasContext(this.defaultCanvasId, this);
      ctx.setLineWidth(this.lineWidth);
      ctx.setStrokeStyle(this.defaultColor);
      //终止弧度
      let eAngle = Math.PI * (this.height ? 1 : 2) + this.sAngle;
      this.drawArc(ctx, eAngle);
    },
    //进度圆环
    drawProgressCircular(startPercentage) {
      let ctx = this.progressContext;
      let gradient = this.linearGradient;
      if (!ctx) {
        ctx = uni.createCanvasContext(this.progressCanvasId, this);
        //创建一个线性的渐变颜色 CanvasGradient对象
        gradient = ctx.createLinearGradient(0, 0, this.diam, 0);
        gradient.addColorStop('0', this.progressColor);
        if (this.gradualColor) {
          gradient.addColorStop('1', this.gradualColor);
        }
        // #ifdef APP-PLUS || MP
        const res = uni.getSystemInfoSync();
        if (!this.gradualColor && res.platform.toLocaleLowerCase() == 'android') {
          gradient.addColorStop('1', this.progressColor);
        }
        // #endif
        this.progressContext = ctx;
        this.linearGradient = gradient;
      }
      ctx.setLineWidth(this.lineWidth);
      ctx.setStrokeStyle(gradient);
      let time = this.percentage == 0 || this.duration < 50 ? 0 : this.duration / this.percentage;
      if (this.percentage > 0) {
        startPercentage = this.duration < 50 ? this.percentage - 1 : startPercentage;
        startPercentage++;
      }
      if (this.fontShow) {
        ctx.setFontSize(this.fontSize);
        ctx.setFillStyle(this.fontColor);
        ctx.setTextAlign('center');
        ctx.setTextBaseline('middle');
        let percentage = this.percentText;
        if (!percentage) {
          percentage = this.counterclockwise
            ? 100 - startPercentage * this.multiple
            : startPercentage * this.multiple;
          percentage = `${percentage}%`;
        }
        let radius = this.diam / 2;
        ctx.fillText(percentage, radius, radius);
      }
      if (this.percentage == 0 || (this.counterclockwise && startPercentage == 100)) {
        ctx.draw();
      } else {
        let eAngle = ((2 * Math.PI) / 100) * startPercentage + this.sAngle;
        this.drawArc(ctx, eAngle);
      }
      setTimeout(() => {
        this.startPercentage = startPercentage;
        if (startPercentage == this.percentage) {
          this.$emit('end', {
            canvasId: this.progressCanvasId,
            percentage: startPercentage,
          });
        } else {
          this.drawProgressCircular(startPercentage);
        }
        this.$emit('change', {
          percentage: startPercentage,
        });
      }, time);
      // #ifdef H5
      // requestAnimationFrame(()=>{})
      // #endif
    },
    //创建弧线
    drawArc(ctx, eAngle) {
      ctx.setLineCap(this.lineCap);
      ctx.beginPath();
      let radius = this.diam / 2; //x=y
      ctx.arc(radius, radius, radius - this.lineWidth, this.sAngle, eAngle, this.counterclockwise);
      ctx.stroke();
      ctx.draw();
    },
    //生成canvasId
    getCanvasId() {
      let uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
        return (c === 'x' ? (Math.random() * 16) | 0 : 'r&0x3' | '0x8').toString(16);
      });
      return uuid;
    },
  },
};
</script>

<style scoped>
.tui-circular-container,
.tui-circular-default {
  position: relative;
}

.tui-circular-progress {
  position: absolute;
  left: 0;
  top: 0;
  z-index: 10;
}
</style>
